-LRB- CNN -RRB- -- Young women at a party attended by about 50 Central Washington University students and other young people were the primary target of spiked drinks , authorities said Saturday .

The incident resulted in `` multiple '' reports of overdoses .

Some of the victims said they had consumed only one or two beverages before becoming ill , Cle Elum-Roslyn Police Chief Scott Ferguson said .

`` Their level of intoxication just did n't seem to make sense , '' he told CNN Radio .

Central Washington University students who attended the party told CNN affiliate KOMO on Saturday that they believe a bottle of vodka at the party had been spiked with a date-rape drug known as `` roofies . ''

They said several people at the party used vodka from the bottle to make mixed drinks . Those who brought their own alcohol , drank beer or did n't drink any alcohol were not affected , the students told KOMO .

Ferguson would not comment on the type of drug placed in the beverages . He said he will ask the Washington State Patrol Crime Laboratory to expedite test results .

Police do not know who spiked the drinks .

`` Whatever occurred up there was n't consensual , '' Ferguson told CNN .

Officers initially responded to an 11:09 p.m. call Friday about a female found unconscious in a vehicle in a grocery store parking lot , Ferguson said .

Friends of the victim told authorities to go to a residence in Roslyn , according to a statement from the Cle Elum Police Department .

An officer entered one room and took a man into custody who was having sex with a semi-conscious young woman , said Ferguson .

Police later determined the woman was the girlfriend of the young man . She exhibited signs of having ingested a spiked drink , Ferguson said , and was taken to the hospital and later released . Her boyfriend was detained and questioned , but not booked . The investigation of that incident -- which authorities described earlier as a `` possible sexual assault '' -- continues , Ferguson said .

Several others at the party appeared to be suffering from overdoses at the residence .

None of the underage people who overdosed meant to get high or unconscious , said Ferguson , and none had more than one or two drinks , KOMO reported . Rather , he said , they appear to be victims of a scheme to render them unconscious and unable to resist or defend themselves .

The woman found in the parking lot remained in the hospital Saturday in stable condition , police said . Twelve people , 11 of them female , initially were taken to hospitals , police said . All except one were released .

The party took place at a rental home about 30 minutes from the university campus in Ellensburg , police said . The owner of the home was not at the party , police said .

Police interviewed about 35 others who attended the party , which they said was organized by a Central Washington student .

The university said it is `` shaken and saddened '' about the incident .

`` CWU strictly enforces state law and university policy on underage drinking and illegal drug use , '' it said , adding that freshmen are educated on drug and alcohol abuse and sexual assault .

`` Despite our best efforts , however , students sometimes make bad choices , '' the university said .

Students identified as being involved with the party will have a conduct hearing that could result in an intensive education course , referral to counselors or suspension , it said .

The school will hold information sessions Saturday and Sunday at residence halls , the statement said .

Police and schools typically warn young people to be careful about ingesting beverages . `` Roofies , '' a street name for Rohypnol , is a tasteless and odorless drug , Boston University says in a fact sheet on its website , and easily dissolves in beverages .

The fact sheet advises students to watch their drinks , avoid punch bowls and not to accept opened beverages .

CNN 's Barbara Hall , Nick Valencia and Jeremy Ryan contributed to this report .

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Central Washington University says students may face discipline

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Man arrested at party , police said

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Substance used to spike drinks is unknown